In the digital age, just about everything has gone digital, and that includes currency. If you've dismissed the concept of a digital currency as the stuff of a few radical tech geeks, it’s high time you became familiar with a currency that is leaving the dollar, yen, and euro in its exponentially increasing digital dust. The value of the bitcoin—the only currency that operates at an enormous international scale free of the shackles of corporate banks and national governments—has skyrocketed in the past several years. It’s all digital, but very real.